1. Field of the Invention
The present invention relates to a lock securing mechanism for securing mutual fitting of connectors for use in connecting electric wires to each other, for example, and to a lock securing member as a component of the lock securing mechanism.
2. Description of the Related Art
One example of conventional lock securing mechanisms for connectors is disclosed in Japanese Utility Model Laid-Open No. 1-165582. For securing mutual fitting between a male housing and a female housing, the disclosed lock securing mechanism for connectors includes a lock securing member which is always attached to one of the housings in a temporarily engaged condition. One housing has a lock arm which is displaceable in a rising direction for locking the male and female housings together. The lock securing member has a flexible latch finger positioned to extend parallel to the lock arm and also abut with an engagement boss provided on the lock arm in the temporarily engaged condition. The other housing is provided with a locking latch engaging the lock arm, and an engagement releasing drive stick for releasing the flexible latch finger from the abutted condition with the lock arm. When the male and female housings are fitted to each other, the engagement releasing drive stick pushes the flexible latch finger upward for shifting the lock securing member from the temporarily engaged position to the completely engaged position where the lock arm is prevented from displacing to hold both the housings in the locked condition.
If the male and female housings are in a half-fitted condition, the engagement releasing drive stick does not act upon the releasing the flexible latch finger to push it up. Therefore, a free end of the flexible latch finger is kept abutted with the engagement boss on the lock arm, making it impossible to further push the lock securing member into the male housing. Accordingly, an incomplete fitting condition of both the housings can be sensed by confirming that the lock securing member cannot be further pushed into the male housing.
To easily sense the half-fitted condition of the male and female housings, a sensing projection is provided on the flexible latch finger of the lock securing member and a sensing portion is formed at a free end of the lock arm. When the sensing portion and the sensing projection are abutted with each other in the half-fitted condition of both the housings, the lock securing member cannot be further pushed into the male housing, thus enabling the half-fitted condition to be easily sensed.
However, the increased number of connector cells requires a great pressing force to fit both the housings together, which leads to the following problem. The great pressing force causes an excessive force to act upon the abutting interface between the sensing portion and the sensing projection in the half-fitted condition. The lock arm and the flexible latch finger are thereby flexed upward to such an extent that the free end of the flexible latch finger is disengaged from the engagement boss on the lock arm and the sensing projection on the flexible latch finger passes beneath the sensing portion of the lock arm, allowing the lock securing member to further enter the male housing erroneously.
Furthermore, the lock securing member is attached to the male housing by inserting a mount rib provided on the lock securing member to a securing member insertion groove formed in the male housing.
However, if there is any play between the securing member insertion groove and the mount rib, the lock securing member is easily apt to incline, which leads to the following problem. Upon the pressing force being applied to the lock securing member, the lock securing member is inclined even in the half-fitted condition of both the housings to such a large extent that the free end of the flexible latch finger is disengaged from the engagement boss on the lock arm to allow further advancement of the lock securing member in spite of that the engagement releasing drive stick are not acting to push the flexible latch finger upward. This may result in a risk of causing troubles because the condition of fitting failure cannot be sensed.
Still another problem is that, if the mount rib is formed to come into close contact with the securing member insertion groove to eliminate a play between the securing member insertion groove and the mount rib, it would be so difficult to insert the lock securing member that some of the parts could not be practically used.
The present invention is intended to solve the problems described above.